I've read several posts on the various internet sites about the proper use/application of dielectric grease to the point where I've managed to confuse my 70 year old mind. Assume you have taken some connectors loose from a battery, cleaned them thoroughly, and now want to reassemble the items. Is dielectric grease applied to each component before they are reassembled, or do you reassemble and cover your work with the grease? Thank you.

Dielectric grease should not be applied to the actual electrical connections where conductivity is desired, it is an insulator and arc preventer. It works great between spark plug boots and the ceramic insulator of the plug to prevent sticking.

_________________
ski

Thanks. Lots of bad advice given on You-Tube, etc.

hi sages- an interesting andsomewhat complicated question. have sought an analysis for a few months. been following an extended discussion of this point over the last few mos. in auto restorer mag(monthly published.). after reading these responses and talking to electricians automotive and licensed, have concluded the following: 1. dielectric grease is non conductive/insulating which is what dielectric means. it can be used to coat connections which are wire nutted where similar metals are connected ie copper to copper,but you must make sure of a positive and tight connection. it suppresses corrosion and presumably shorting caused by moisture intrusion and other corrosive agents. i have used it on some auto connections and house electrics w/o a problem. 2. another type of grease used is anti oxidation (brand name no oxy) which is conductive . it is intended for wire connections where metals are dissimilar(ie- copper to aluminum) . it suppresses galvanic corrosion which happens with a dissiilar connection. have recently used it on outside house connections where moisture andhumidity cause problems such as front lawn post lights here is south fla. will wait and see how this holds up. have heard some differences of opinion on both greases from electricians . a mechanic who has done good work for me without sending me to the cleaners, says dont use either on auto connections since given the much lower power outputs , its unnecessary and could hasten shorts. he said just makesure connections are clean and tight . hope my uncle dan who is our resident auto electric sage here , will chime in and critique my thoughts. thanks bob f

Bob's analysis is correct.

That said, I've seen people use, and recommend, dielectric grease on the actual connection as well as e.g. on the ceramic of a plug/boot. The key is that the metal to metal connection is typically going to be made whether the grease is there or not, i.e. it'll squish the grease from between the two metals making contact, there will be sufficient connection, and the grease takes up any spaces where there would otherwise just be air and where corrosion would start. I've heard people say they slather it, e.g., on the firewall connector block, then plug in all the connections and have no issues with electrical connectivity (and the connectors don't corrode because the grease is now protecting them from the air). This seems to make sense to me for a couple reasons. First, when you snap two metal connectors together, there will be sufficient area where the metals are actually scraping together and deliver whatever current needs to get through. Second, it would be almost impossible to put that grease on two connectors already connected and not get some between the connectors where airspaces are.

I plan to (finally) wire my firewall connector block over Christmas break; I guess I'll find out if they're right. Right now I have the square hole with a bunch of wires running through it (foam around them as a makeshift grommet and to keep the air off my legs).

my two cents....

brian

_________________
https://tinyurl.com/yynpj4v2

For 2 decades I've always put the battery cables onto the battery wet with Vaseline petroleum jelly (drugstore) or LPS-3 spray. Coat everything before assembly. Then as Brian said, the metal-to-metal contact will happen by itself, but the lube seals out all moisture that causes corrosion. My 2 cents. P.

_________________
"Louise", a 1976 Dart Custom project, (now sadly reverted to being just an "organ donor" to our other project Darts.)

Correct. And there is nothing substantial behind the idea that you shouldn't use dielectric grease on the actual metal terminals. The terminals will make a perfectly fine connection to each other when you push them together; the grease will not prevent that -- it will just be pushed out of the way of the actual metal-to-metal contact area as you push the terminals together. However, the grease that remains on the non-contact areas will prevent corrosion.
Wire nuts really are not proper items to use in automotive wiring. These, on the other hand, are terrific.
Or NoAlOx, or Ox-Gard (to guard against marauding herds of oxen), etc. This is basically vaseline (petroleum jelly) with green zinc powder mixed in. It's intended for use in household wiring when working with aluminum wiring, but can also be applied to vehicle electrical connections. It can protect against marginal contact while also preventing corrosion by dint of its being a grease.
His principle is wrong. Auto electrics are not "lower power output". They're lower voltage, which means higher current for any given wattage. A 60-watt car headlight filament, for example, takes 4.6 amps to run. A 60-watt household bulb takes 0.5 amp to run.

Our cars were cheaply built a long time ago, during a time when everyone was expected to trade in for a new car every year or three. Many connections are made with mediocre, unplated terminals that have little or no environmental sealing. Grease of one sort or another is a good idea. It's less necessary on newer cars made with better-sealed, plated connectors.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Its my belief the grease also provides one other not yet mentioned long term benefit. That is the the grease provides a thermal path thru the air spaces its fills to keep the working terminal connection cooler. Any increase in temp enhances oxidation/corrosion, making for a poorer connection, which then becomes hotter, and the cycle continues.